It's a fun discussion and I have no real axe to grind, just some observations made over the years.
I started off with the jacket and tie culture, even while at CATC Hurn, I can't remember when we largely stopped wearing them, probably in the 1990s. I have never found a tie to be comfortable to wear anyway, so I was glad to go without. One of our STPOs would still wear a collar-and-tie to work on night-duties. I think a return to formal ops-room dress would be about as popular as the return of a smoking ops room.
A good point was made earlier though. I've just been reading the link on the other thread about EC driven cost-reduction, and a lot of 'stakeholders' are keen to see ATC staff paid less. Over the coming years, these holders of purse-strings will be visiting towers and looking through viewing-gallery windows. Notwithstanding the first-class service that ops-room staff provide, (about which they know little), these 'suits' will inevitably question why people dressed for the beach, golf-course or whatever, receive the remuneration that they do.